Removing everything but letter from array of strings

[ForsakenSoul]

Hello,
Currently I'm trying to make a project that reads a bunch of strings and stores them into an array of strings. The problem is I need to remove any characters that don't belong, because when I get the array of strings I then need to sort them alphabetically. I only need the words and no punctuation or numbers. Here is the file I must read from.

Tell friends that you have eleven (11) fingers,
and will prove it! Touch each finger of left hand,
counting "One, two, three, fou4r, five".
Now count the fingers on your right hand,
"Six, seven, eight, nine, ten".
Say "Funny, Let's try again".
This time backwards, pointing to the fingers
of the left hand say "Ten, nine, eight, seven, six ...".
Stop, hold up the right hand,
say "Plus five equals eleven!".
Do this quickly, without pausing!